Now made for iPhone Duo: half open, your level stands on the fold as a gauge. One honest fitness level from your Apple Health workouts – no account, no ads.
iPhone · iPad · with Apple Health
4Level is made for ambitious amateur athletes who already train regularly and want to know: How fit am I really — and am I sticking to what I set out to do?
4Level analyses the workouts you already record. It does not create training plans, workouts or coaching advice and does not replace a coach. You decide how you train; 4Level measures, explains and keeps you honest.
One number from three building blocks:
Calculated for every single day back to your first workout, using only what was known on that day. Every value shows whether it was measured or estimated; the whole formula is explained in the app.
Set per sport — running, cycling, hiking, swimming, strength — how often and on which days you intend to train, or train as you feel like it. Add weekly, monthly or yearly kilometre targets if you like (not for strength). 4Level shows whether you are ahead or behind right now, a 26-week heatmap, your streak in weeks and your month balance. Flexible by design: ran Monday, Tuesday and Saturday instead of Monday, Wednesday and Friday? The week still counts. Measured retroactively for the last 26 weeks if you want.
After each session dots fill the gap at the bottom of your level ring; when the ring closes, you are recovered. How long that takes depends on the load and intensity of the session and on your fitness. 4Level also reads resting heart rate, heart rate over the day, HRV and cardio recovery, analyses your history once and adapts the recovery time to how you actually recover — Apple Watch or another device that writes heart rate to Apple Health. A notification when you are recovered is optional.
Half open, the scale of your dial unrolls along the fold into a level gauge: on the table the dial stands above the fold and your logbook lies below, in the book pose the gauge stands upright between instrument and logbook. Fully open, every tab shows two pages; closed and turned sideways, dial and history stand side by side. Folding keeps your tab, selection, open sheets and scroll position. On every other iPhone and on iPad, 4Level looks and works as before.
Fitness, fatigue and freshness (CTL, ATL, TSB) show whether you are rested, building or overloaded — judged on the trend of the last days, not on how tired you are right after a session. Race predictions for 5 km to marathon come from your runs of the last 120 days: pace and, if you record it, heart rate.
Yearly goals with a marker where you should be today, this year against last year and your best year, weekly volume, records, all years at a glance. Plus a searchable list of all your workouts.
4Level reads from Apple Health — everything your Apple Watch, Garmin Connect, Strava, Zwift, Wahoo and other apps write there. You choose per sport which app's recording counts; the same session recorded twice counts once, and missing heart rate, climbing or power is filled in from the other recording.
4Level speaks English, German, French, Spanish and Italian and follows your device’s language. To use a different language in 4Level only, tap the Language row in the app’s settings — it opens 4Level in the iOS Settings. iOS shows a Language row there only if you have more than one preferred language; otherwise add the language first under General → Language & Region.
The level is a training aid, not a medical assessment. Try the demo without any data.
Swipe through the app on iPhone and iPad.
No account, no server, no analytics, no ads. Data is read from Apple Health and stays on your device.
30 days free with everything included. Afterwards 4Level Pro: a yearly subscription (renews automatically, cancel anytime in your Apple Account settings) or a one-time lifetime licence.
Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
30 days free, then €1.99 per year or €9.99 once (lifetime).
Prices may vary by country.
Last updated: October 14, 2026 (version 1.3)
4Level is made by Robert Poetzsch (robspace.de), who is responsible for this app within the meaning of the GDPR. Contact: support@robspace.de. The postal address is in the legal notice (Impressum) on this website.
What the app reads. With your permission, 4Level reads from Apple Health: workouts (sport, time, duration, distance, energy, elevation, the app that recorded them), heart rate, resting heart rate, heart rate variability (HRV), cardio recovery, cycling power, body weight, VO₂max, date of birth and sex. You choose in Apple's permission screen which of these 4Level may read. 4Level never writes to Apple Health.
Where the data lives. Only on your iPhone/iPad. 4Level keeps a copy of the workouts, daily heart values (resting heart rate, lowest hourly heart rate, HRV, cardio recovery) and the calculated history in its private storage, excluded from iCloud backups. There is no 4Level server, no user account, no analytics, no advertising, no tracking and no third-party SDKs. Health data is never sent anywhere and never used for advertising. The developer receives none of your data.
Notifications. 4Level can notify you when your recovery is over. This is off by default and asks for permission only when you switch it on (Settings → Recovery). The notification is scheduled on the device itself; no push service is involved and nothing is sent.
Purchases. Subscriptions and the lifetime licence are handled entirely by Apple. The app only asks the App Store on the device whether a purchase is active; the developer receives no payment or personal data.
Your control and your rights. Settings → Apple Health → "Delete 4Level's data" removes everything 4Level stored. To revoke read access: iOS Settings → Apps → Health → Data Access & Devices → 4Level. Deleting the app removes all workouts and the calculated history as well. Only a small purchase record stays in the device's keychain (start date of the free trial, purchase status, which reminders were shown), so that reinstalling does not restart the trial. It contains no health data, is not synced and never leaves the device. Your data in Apple Health is never changed. You have the right of access, rectification, erasure, restriction of processing, data portability and objection (Art. 15–21 GDPR). Because the app sends the developer no data about you, there is nothing the developer could disclose, correct or delete; questions are still welcome at support@robspace.de. You have the right to lodge a complaint with a data protection supervisory authority, for example the Hessian Commissioner for Data Protection and Freedom of Information (HBDI).
Health information. The fitness level is a training aid, not a medical assessment.
This website. This website is hosted by Hetzner Online GmbH on a server in a data centre in Falkenstein, Germany. When you open a page, the web server automatically logs your IP address, the date and time, the requested page or file, the HTTP status, the number of bytes transferred, the referring page (referrer) and your browser’s user agent. These logs are used solely to operate and secure the website; the legal basis is Art. 6(1)(f) GDPR (legitimate interest in secure, stable operation). They are deleted automatically after 14 days at the latest, are not analysed and are not passed on unless required by law.
The website sets no cookies, uses no analytics or tracking and embeds no content from third parties. Only your language choice is kept in your browser’s local storage, and not for tracking. Fonts are served from this server; no connection is made to Google Fonts or other font services.
Changes. If the app's handling of data changes, this policy is updated and the date above changes.
A history of every update to 4Level.
Robert Poetzsch
Brückenstr. 8A
65719 Hofheim am Taunus
Germany
Email: support@robspace.de
Website: robspace.de
In accordance with Article 30 of Regulation (EU) 2022/2065 (Digital Services Act), we declare that we act as a trader within the meaning of EU consumer protection law when offering 4Level through the Apple App Store.
Robert Poetzsch, Brückenstr. 8A, 65719 Hofheim am Taunus, Germany.
As a service provider, we are responsible for our own content on these pages in accordance with general legislation pursuant to Section 7(1) DDG. According to Sections 8 to 10 DDG, however, we are not obligated to monitor transmitted or stored third-party information or to investigate circumstances that indicate illegal activity. Obligations to remove or block the use of information under general law remain unaffected. However, liability in this respect is only possible from the point in time at which we become aware of a specific legal infringement. If we become aware of any such legal infringements, we will remove the relevant content immediately.
This website may contain links to external third-party websites over whose content we have no control. Therefore, we cannot accept any liability for this third-party content. The respective provider or operator of the linked pages is always responsible for the content of the linked pages. The linked pages were checked for possible legal violations at the time of linking. Illegal content was not recognizable at the time of linking. However, permanent monitoring of the linked pages is unreasonable without concrete evidence of a legal violation. If we become aware of any legal infringements, we will remove such links immediately.
The content and works on these pages created by the site operator are subject to German copyright law. Duplication, processing, distribution, and any form of commercialization of such material beyond the scope of copyright law requires the prior written consent of its respective author or creator. Downloads and copies of this site are only permitted for private, non-commercial use. Insofar as the content on this site was not created by the operator, the copyrights of third parties are respected. In particular, third-party content is marked as such. Should you nevertheless become aware of a copyright infringement, please inform us accordingly. If we become aware of any infringements, we will remove such content immediately. The fonts used on this website (DM Sans, Outfit, JetBrains Mono) are licensed under the SIL Open Font License 1.1 and are served from this website.
Apple Inc. is not responsible for the app, its content, or any claims related to the app. Apple Health, Apple Watch, Garmin Connect, Strava, Zwift and Wahoo are trademarks of their respective owners; 4Level is not affiliated with them.
4Level — Version 1.4
© 2026 Robert Poetzsch
4Level is developed as a personal project in my free time.
Responses to support inquiries may take some time.
Bug reports are always welcome and appreciated!